On a wind turbine with a disc brake attached to the generator, or alternatively to the hub, thermal expansion in the brake disc or an other component of the brake system may occur during operation. The components of the brake system may be exposed to mechanical stress coursed by different thermal expansion, for example in the disc brake and the generator or the hub.
Up to now, disc brakes on geared turbines have been positioned on the rotating shaft of the wind turbines. When building direct drive turbines without rotating shafts the disc brake will need to be mounted on the generator, or on the turbine hub. Typically, the disk brake will heat up during use, and for that reason the thermal expansion will generate reaction forces. Also during normal operation, different temperature between generator and disc brake can generate reaction forces.